The UN created a two state solution to "Palestine/Levant" in 1947-48. One part Jewish/Israel other part "Arab"/"Islam"-etc.
Neighboring Arab/Muslim states rejected that solution and started the first of many wars against Israel, goal being to destroy that State/Nation and kill~expel all the Jews. Despite repeated defeats, the Arab/Muslims continue to fight/attack.
Care to remind us of your socialist/communist position rejecting the state of Israel, result of UN "solution"?
"Vietnam" started as a UN "solution" for French Indo-China, post World War Two and was initially a French war there. USA took over when France bailed out. Communist China and Russia stayed involved until North Vietnam "won".
Iraq was result of the League of Nations, UN precursor, and failure of UN to curb and later remove Saddam Hussein and Baath Party dictatorship. Largest WMD in Iraq was the Environmental/Ecological draining of the Southern, Coastal Marshlands destroying diverse species habitats, decimating Persian Gulf fishery~ecology, and near genocide of millenial old "Marsh Arab" peoples and culture. Single largest human caused ecological disaster to date.
Saddam failed to comply with terms of cease-fire from previous war ejecting him from Kuwait, USA and other nations ran out of patience and didn't want to bear costs of containment for many more decades to come. Unfortunately the situation became a surrogate for Iranian aggression and insurrection inside of Iraq and no one wanted to deal discouraging blows to Iran for it's interference.